tests: core: Convert: Remove the gray code.
tests: core: Convert: Remove the gray code.

It's not working and parts of the code causes python errors with
floating point vs. int params to hex().

Signed-off-by: Cyril Hrubis <b1e90efd3b808b8e0bcf2a9a55fd8b9a779bfd81@ucw.cz>

gfxprim/gfxprim,gfxprim/gfxprim,gfxprim/gfxprim,gfxprim/gfxprim,gfxprim/gfxprim